Subproject: Sediment contact test with Caenorhabditis elegans (Nematoda)
Aims of the project

While the water quality has improved considerably in the last years due to water protec-tion, in many European catchment basins highly polluted sediments still represent a legacy of the industrial era, strongly influencing the water quality in the future. Sediment bound contaminants can be remobilized by bioturbation, floods, or dumping of dredged material. Therefore, monitoring and assessment of sediment quality plays an important role not only for national legislation, but also for the implementation of the EU water framework directive. The EU water framework directive (EWFD) aims to achieve a good ecological and chemical state for surface waters in European catchment basins till 2015. The reduction of anthropogenic water pollution from diffuse and point sources should be reached by a combination of specifications of emission limit values and immision orientated quality objectives. Against this background, there is a demand for the application of sediment contact tests: While the commonly used bioassays reflect only insufficiently contaminant bioavailability, sediment contact tests (whole sediment tests) have a higher ecological relevance. Sediment contact tests are biological tests that determine the effect of whole sediment on organisms, considering all possible contaminant uptake routes for the test organism (particle contact, food, pore water). The complexity of the matrix sediment (particles and water) make high methodological demands on the test systems. The bioassays must be able to differentiate between anthropgenic disturbances (e.g. pollution) and the influence of natural factors (e.g. grain size), to enable a risk assessment. The aim of the investigations of the joint research project SeKT (Sediment Kontakt Tests) was to evaluate the applicability of the sediment contact tests for a possibly wide range of different types of sediments. The definition of reference conditions and stand-ardized control sediments are prerequisites for:

1. the determination of toxicity thesholds
2. the comparability of sediment contact tests with in a test battery
3. the application of sediment dilution series.

Therefore, the first step was the investigation of uncontaminated natural and artificial sediments with a test battery, to determine the response of the test systems to important sediment properties, such as TOC and grain size. The results could explain the variabil-ity of the different tests with the inverstigates sediment properties. Informations on the variability helped to define more reliable toxicity thresholds for the various tests. Addi-tionally, artificial and natural control sediments were defined for the whole test battery.

More information „SeKT Flyer“

Publications originating from this project: 

Höss S, Ahlf W, Fahnenstich C, Gilberg D, Hollert H, Melbye K, Meller M, Hammers-Wirtz M, Heininger P, Neumann-Hensel H, Ottermanns R, Ratte H T, Seiler T B, Spira D, Weber J, Feiler U (2010) Variability of freshwater sediment contact tests in sediments with low-level anthropogenic contamination – Determination of toxicity thresholds. Environ Poll 158:2999-3010.

Feiler U, Höss S, Ahlf W, Gilberg D, Hammers-Wirtz M, Hollert H, Meller M, Neumann-Hensel H, Ottermanns R, Seiler T-B, Spira D, Heininger P (2013): Sediment contact tests as a tool for the assessment of sediment quality in German waters. Environ Toxicol Chem 32:144–155.